I think original 7D is really good value right now and won't depreciate for some time. You can get a used one in the low to mid 400s in good condition, it does pretty good video as well considering its age, and I like the AF system despite having fewer points than more modern cameras.
5D Mark II is inferior but also costs less, in the low 700s, just another option to consider.
I also think the 1D Mark IV is a good buy if you find one below $1100 in decent condition. I actually like 1.3x crop, it's a nice compromise between reach and IQ for me, and AI servo is just so much more responsive in 1-series bodies.
The 6D's forte is low light, with the super sensitive center AF point. There's a reason why used prices don't really dip below grey market prices (both ~$1000), it's a good enough camera for people who don't shoot action much.